A belt press filter is an industrial machine, used for solid/liquid separation, such as dewatering of sludges in the chemical industry, mining processes, and water treatment. Belt press filters are also used in the production juices and wine. Filtration is primarily achieved by passing a pair of filtering cloths or belts through a system of rollers. The system takes a sludge or slurry as a feed and separates it into a filtrate and a solid cake.
Belt press filters comprise a frame and an assembly of rollers that support and drive an upper continuous belt and a lower continuous belt that are in operable communication with each other. The belts are permeable to allow the extrusion of the liquid therethrough. The mixture is first placed on the lower belt, then sandwiched between the upper and lower belts. The belts and the retained mixture then pass through a wedge section where the mixture is distributed between the belts, and an initial volume of liquid is removed. The belts then pass through a series of progressively smaller diameter rollers where the retained mixture is compressed for further liquid removal. The belts are then separated and the dry “cake” is removed from the belts, generally by a scraping apparatus. The belts then pass through one or more belt washers, after which the process is repeated. The liquid from the extrusion and belt washing processes are collected for disposal.
Belt press filters are used in a range of areas, including urban sewage and wastewater treatment, metallurgy and mining, steel plants, coal plants, breweries, dyeing, tanneries, as well as chemical and paper factories. As such, the mixtures processed by the belt press filter can include mixed sludge, mineral slurry, dust sediment, selected coal washing mud, biological sludge, primary sludge, and straw, wood or waste paper pulp.
The choice of belt is critical to the operation of the belt press filter, wherein there are various materials and weaves available. Lighter cloths produce a clearer filtrate and do not block as rapidly, but their durability and life span is significantly shorter than heavier cloths. Both seamless and seamed belts are available. Seamed belts wear faster at the seam and cause wear at the rollers. Zipper-type and clipper-type seamed belts are also available, with the zipper-type having a longer life span as they provide more continuity.
Given the abrasive or caustic nature of the mixtures being processed, the belts themselves must be periodically changed. Further, considering the complex nature of the belt press filter, the belt changing process is a highly complicated, laborious, and often dangerous process that traditionally requires a team of personnel and an high level of physical exertion.
There exists a need in the industry to quickly and safely change zipper type belts using fewer personnel.